The present invention relates to an improved pellet stove, and, in particular, to an improved gravity fuel delivery system for a pellet stove.
Prior to the advent of centralized heating by use of hydrocarbon fuels, most residential structures were heated by fireplaces or stoves using wood or coal as fuel. Even today many rural homes continue to be primarily or secondarily heated by such heat sources. However, such heat sources are infamous air polluters, especially in the amount of particulate matter emitted into the atmosphere. During adverse weather conditions, such as periods of stagnant air, many jurisdictions ban the use of such heat sources for so long as such conditions continue to exist.
Relatively recently pellet stoves have been introduced that lower obnoxious emissions. Many models utilize electric motor driven fans or blowers to direct air into the stove's combustion chamber and to drive an auger to deliver pellets to the combustion chamber. Such stoves that are dependent upon electricity are not useful during power outages or in locations where there is no power.
Pellet stoves have been developed which use gravity feed to deliver pellets from a hopper to the combustion chamber, and use the natural draft generated by heated air flowing from the combustion chamber to the outlet of the venting system to obviate the need for electricity to operate fans and feed augers. However, many of these stoves do not efficiently combust the pellet fuel which results in particulate emissions which exceed EPA and/or state emission standards. Many such pellet stoves suffer from “burn-back” problems in which pellets in the feed delivery system and/or pellet supply hopper are ignited.